Presently, the types in head of windshield wiper arm are many in variety. Different type design of wiper arm head must be coordinated with its exclusive jointer to enable securely joint each other. Such as USA issued patents U.S. Pat. No. 6,516,491, U.S. Pat. No. 6,643,889, U.S. Pat. No. 6,668,419, U.S. Pat. No. 6,810,556, U.S. Pat. No. 6,836,927, U.S. Pat. No. 6, 836,926, U.S. Pat. No. 6,874,195, U.S. Pat. No. 6,886,213 and U.S. Pat. No. 6,904,639 as well as USA published patents US2004/0025280 and US2004/0098821, all disclosed their different types of wiper arm head in association with its exclusive jointers. In which, a conventional wiper arm 1 having a trapezohedron shaft 2 at its head with its exclusive jointer is shown in the FIG. 1 through FIG. 7. The free end of the wiper arm 1 is pivoted with a trapezohedron shaft 2, and its other fixing end is soundly locked on the output shaft of the wiper motor (not shown in the figures); an elastic foldable articulation 4 is fitted near its fixing end to enable said wiper arm 1 being folded in upright position during replacing worn wiper blade by new one. Wherein, a bezel notch 2a is contrived in the wider surface of said trapezohedron shaft 2; and a spindle hole 2b is created in its central axial line to be inserted a fixing spindle 3 in order to enable itself rotate freely between a pair of parallel and symmetrically protruded holding plates 1a:1b on the both sides in front end of said wiper arm 1 (as shown in the 1A-1A sectional view of the FIG. 1).
Refer to FIG. 3 through FIG. 5, the exclusively coordinated jointer of said wiper arm 1 with said trapezohedron shaft 2 on the head comprises a main body 10, a sliding canopy 20 and a stopping plate 30; wherein, a trapezohedron receptacle 11 is concaved in the center of said main body 10 in upright position with opening upwards; a fixing hole 12 is perforated at the center in bottom side of said trapezohedron receptacle 11, and a pair of symmetrical sliding seat is formed on both sides of said trapezohedron receptacle 11; a unitary-molded parallel and symmetrical inset clip 14 is molded at the bottom portion of each said sliding seat 13; in which, a pair of parallel and symmetrical upper sliding rail 131 is built on the top surface of each said sliding seat 13, and a pair of parallel and symmetrical lower sliding track 132 is created the joint with said inset clip 14 at its bottom side; Said sliding canopy 20 is a cannulation compassed by a front side, a left side, a right side and a top side; a pair of parallel and symmetrical lower sliding rail 21 is formed at bottom in each inner wall of its left side and right side, and a protruding bar 22 is molded at center in inner wall of its top side; Said stopping plate 30 is pressed by a rectangular metal plate with both long lateral edge being bent downwards to form a pair of parallel and symmetrical upper sliding track 31; a indented downwards elastic bulge buckle 32 and an infixing bar hole 33 is respectively pressed at the center of its top side. By means of squeezing said protruding bar 22 inset in said sliding canopy 20 from infixing bar hole 33, said stopping plate 30 can be fixed on the inner wall in top side of said sliding canopy 20 (as shown in the 4B-4B sectional view of the FIG. 4); by further means of aligning said lower sliding rail 21 on said sliding canopy 20 and said upper sliding track 31 on said stopping plate 30 respectively with said lower sliding track 132 and said upper sliding rail 131 on said stopping plate 30, the opening of said trapezohedron receptacle 11 on said main body 10 (as shown in the FIG. 5).
The rigging assembly of said wiper arm 1 with said trapezohedron shaft 2 on the head and windshield wiper is shown in the FIG. 6 through FIG. 9. First, by means of grasping the central position of said wiper elastic strip 5 from said parallel inset clip 14 at the bottom of said main body 10 and riveting through said fixing hole 12, both of said main body 10 and said wiper elastic strip 5 can be intimately engaged steadfastly (as shown in the 8C-8C sectional view of the FIG. 8); Next, slide said sliding canopy 20 outwards to prevent said stopping plate 30 from blocking the opening of said trapezohedron receptacle 11 on said main body 10 (as shown in the FIG. 6); Then, with keeping said bezel notch 2a face upwards, by means of aligning said trapezohedron shaft 2 on the head of said wiper arm 1 with the opening of said trapezohedron receptacle 11, said trapezohedron shaft 2 can be smoothly mounted in said trapezohedron receptacle 11 (as shown in FIG. 7); subsequently, slide said sliding canopy 20 towards said wiper arm 1 up to said elastic bulge buckle 32 on said stopping plate 30 falling into said bezel notch 2a on the top surface of said trapezohedron shaft 2 with snap sound, the rigging couple of said wiper arm 1 with windshield wiper is finished now. Consequently, said trapezohedron shaft 2 is embedded to prevent from detaching out of said trapezohedron receptacle 11 (as shown in the 8C-8C sectional view of FIG. 8); furthermore, with free rotation function of said trapezohedron shaft 2, said wiper is enabled to sway or tilt on said wiper arm 1 in some limit (as shown in the hypothetical dash-line image of the FIG. 9). However, during the replacement of worn wiper by new one, the aforesaid jointer of said trapezohedron shaft 2 has the drawback of being easy to inadvertently drop and hurt the windshield or the lacquer of the hood. Refer to FIG. 10 and FIG. 11, the worn wiper must be first dismantled from said wiper arm 1 before replacement by means of applying an upwards force on said wiper arm 1, which tightly stays with the windshield G in horizontal position (as shown in the FIG. 10); With pivot of said elastic foldable articulation 4, said wiper arm 1 become in upright position to enable the wiper scraping blade 6 folded away from windshield G (as shown in FIG. 11); Then, the dismantle procedure can be start to proceed with steps shown in each sectional view of the FIG. 12 as below:
a. With fingers holding on both lateral sides of said sliding canopy 20, apply a force on it towards the lengthwise direction away of the head in said wiper arm 1 (as shown the force F action illustration of the FIG. 12);
b. If acting force F is greater than the engaging force of said elastic bulge buckle 32 in said stopping plate 30, said elastic bulge buckle 32 can be slipped out of said bezel notch 2a on said trapezohedron shaft 2 (as shown in B view of the FIG. 12);
c. During said sliding canopy 20 sliding outwards, said stopping plate 30 will not block the opening of said trapezohedron receptacle 11 any more (as shown in C view of the FIG. 12); then, under the gravity, said wiper scraping blade 6 and said main body 10 will separate off said trapezohedron shaft 2 on the head of said wiper arm 1 for their total weight (as shown in D view of the FIG. 12) to finish the dismantle procedure of worn wiper.
In aforementioned step a, said wiper arm 1 can unexpectedly re-bounce back to horizontal position with hurt on the surface of said windshield G in consequence of a horizontal component force F1 of said acting force F will simultaneously apply a torque on the head of said wiper arm 1 to cause the reaction of spring force on said elastic foldable articulation 4; And, In step b, the apply force can easily be too much so that said sliding canopy 20 detach off said main body 10 to drop on said windshield G or the ground for having acting force F greater than the engaging force of said elastic bulge buckle 32 ; Furthermore, in step c, any careless will let total worn wiper scraping blade 6 hit and hurt said windshield G in bad consequence of dropping without catching it in time.